This application claims the priority of German Patent Document No. 101 50 054.8, filed Oct. 10, 2001, the disclosure of which is expressly incorporated by reference herein.
The present invention relates to a manual transmission.
DE 199 20 064 C2 discloses a gear wheel variable speed transmission for motor vehicles. Two pairs of gear wheels, which can be coupled in a known manner with the input shaft by way of a sliding sleeve and an assigned stationary wheel, can be rotated on an input shaft. These gear wheels, which are mounted so as to rotate on the input shaft, are in permanent engagement with assigned gear wheels, which are connected stationarily to an output shaft. A single gearshift rod is used to shift the two sliding sleeves. On the gearshift rod there are two gearshift forks, which can be displaced in relation to said gearshift rod. The gearshift forks are assigned to the two sliding sleeves and can be coupled selectively to the gearshift rod by way of electromagnetic actuators. By actuating one of the two actuators, a pin, assigned to the gearshift fork, slides into a recess of the gearshift rod and produces a shape-locking connection between the gearshift fork and the gearshift rod. When the gearshift rod is slid axially, the respective gearshift fork and the assigned sliding sleeve are also moved along with the gearshift rod. Thus, the electromagnetic actuators form an xe2x80x9cinternal gearshift mechanismxe2x80x9d of the transmission.
In such a transmission all of the gearshift bodies, that is all of the gearshift forks and gearshift rockers, are assigned to a single gearshift rod. Thus, it is not possible to move several gearshift elements simultaneously in different shift directions.
An object of the invention is to provide a manual transmission with expanded xe2x80x9cdegrees of gearshift freedomxe2x80x9d.
One of the aspects of the invention is directed to a manual transmission, in which two separate actuating devices are assigned to the individual gearshift bodies, that is the gearshift forks and/or the gearshift rockers. A gearshift body can be actuated selectively by one or the other actuating device. The actuating devices are preferably gearshift rods.
The gearshift rods run in essence parallelly side-by-side through recesses of the gearshift bodies. Each individual gearshift body has two actuators, which can be actuated, for example, electromagnetically or mechanically and are assigned to the two gearshift rods. By actuating the actuators, a coupling between the gear shift rod and the gearshift body can be produced.
One important advantage of the invention over the aforementioned prior art is that two coaxially arranged gearshift bodies can be shifted simultaneously, especially in different shift directions.
The gearshift elements can be coupled with the gearshift rods by the electromagnetic actuators. That is, in the uncoupled state the gearshift rods can slide relative to the gearshift bodies. A further development of the invention provides that the gearshift bodies can be coupled with a gearshift rod not only in a specific position but also that there are several xe2x80x9csliding positionsxe2x80x9d of the gearshift rod, in which it is possible to couple the gearshift rod with the gearshift body. To this end, the gearshift rod can have several recesses, in which an assigned actuator of the gearshift body can engage. Preferably the number of recesses of the gearshift rod in the area of one actuator is equivalent to the number of shift positions of the assigned gearshift body. A gearshift fork and/or a gearshift rocker has usually one neutral position and two shift positions. In this case the gearshift rod has three recesses in the area of the gearshift body.
Preferably the gearshift rods can be actuated independently of one another. However, it can also be provided that the gearshift rods can be actuated simultaneously, but preferably only in different xe2x80x9csliding directionsxe2x80x9d.
According to a further development of the invention, the gearshift rods can be coupled together by a mechanical coupling element. Owing to the mechanical coupling of two gearshift rods, they can be actuated oppositely directed by a single setting element, for example, a single hydraulic cylinder or an electric control motor. The coupling element can be, for example, a rocker lever, disposed in the transmission, or a gear wheel, which meshes with gear rack segments of both gearshift rods.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.